Defect scan is usually performed with respect to a storage device such as a hard disk drive or the like. The defect scan is an operation of writing data to a storage medium such as a magnetic disk, test whether the data can be normally read or not, and detect a defect sector in which data cannot be normally read due to a defect, such as a scratch on the medium, etc. A physical address of the defect sector is registered in a defect list and the defect sector is set to be unusable. To set the defect sector to be unusable, when a logical address is mapped to a physical address after the defect scan, so-called skip processing may be executed. In the skip processing, the logical address is not mapped to the physical address of the defect sector but is allocated to the physical address of a sector subsequent to the defect sector. Alternatively, to set the defect sector to be unusable, so-called replacement processing may be executed. In the replacement processing, use of the defect sector is avoided by preparing a spare region in the storage medium, mapping a logical address which should be mapped to the physical address of the defect sector to a physical address of a normal sector in the spare region instead and using the normal sector in the spare region instead of the defect sector. Even if several defect sectors are included in the storage medium, the storage device may be shipped as a conforming item by using the defect scan.
As the storage capacity increases, the time required for the defect scan increases and the entire manufacturing process time also increases.
Such defect scan may be executed not only for the storage device having the magnetic disk, but also for a storage device having semiconductor memory such as a solid state drive (SSD), etc.